Re: Marketing/advertising have no ethic, so asking for ethical use is useless...
@Ragarath, I don't agree with you. When I take a portrait, my subject wouldn't be very happy if I left this or that ugly pimple in their face. So I eliminate it or at least tone it down. Is that a lie? You may say so, but no one likes to look at an unpleasant picture, much less so of themselves.
But it doesn't start at post production. Already the way the lighting is set up for taking the picture, to emphasis or attenuate certain features, isn't that a lie, too? I can only guess that you would agree with me that we're not required to only take portraits in harsh front light but can use lighting creatively. So, if someone has an unfavourable feature, I try to set pose and light up to make it look better. And with unfavourable feature and look better I mean in the perception of the model/client.
While some "faults", e.g. a difficult waistline, are easier to "correct" with setting up the shot, others, such as a spot in the face, are easier to "correct" in post-production. Both are "lies". Where is the ethical limit?
Check the terms of reputable press photo agencies, they have stringent conditions - you may change exposure and negligible features (e.g. dust on the lens). For me, with regard to post-production, I wouldn't touch a waistline or double chin etc. But I do "correct" minor, temporary features, like a spot on the nose (not for press though). The limit is that I don't change a material feature of the photo.